1. Field of the Invention
The present invention relates to a voice signal processing device capable of detecting a vowel / a consonant from a voice signal.
2. Description of the Related Art
FIG. 1 is a block diagram of a prior art signal processing device. The numeral 11 indicates a filter control section into which a signal containing a noise, is inputted and which detects the signal or the noise, the numeral 12 indicates a BPF group having numerous band-pass filters, and the numeral 13 indicates an adder. That is, the filter control section 11 controls a filter coefficient of the BPF group in response to the noise or signal of an input signal, and the BPF group 12 has band-pass filters configured in a manner to divide the input signal into the proper bands and determine the pass band characteristic by a control signal from the filter control section 11.
The operation of the prior art signal processing device configured as described above will be explained hereinafter.
An input signal in which a voice is superimposed by a noise is supplied to the filter control section 11. The filter control section 11 determines from the supplied signal a noise component corresponding to each band of the BPF group 12, and supplies a filter coefficient which allows the noise component not to pass through the BPF group 12 to the BPF group 12.
The BPF group 12 divides the input signal into proper bands, allows the input signal to pass through as appropriate by utilizing the filter coefficient inputted from the filter control section 11 for each band, and supplies the signal to the adder 13. The adder 13 mixes signals divided by the BPF group 12 into proper bands to obtain an output.
With the above operation, the pass level of noise-contained bands of the input signal is decreased by the BPF group 12. As a result, a signal having an attenuated-noise component is obtained.
However, the numerousness of noise is not always coincident with articulation and accordingly, a prior art signal processing device has a problem in that a noise can be held down, but the articulation is not improved.